Tropical Cyclone Olga rapidly intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale during Sunday morning. At 11:00 a.m. EDT on Sunday the center of Tropical Cyclone Olga was located at latitude 15.6°S and longitude 119.1°E which put it about 365 miles (590 km) north of the Port Hedland, Australia. Olga was moving toward the south-southwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 140 m.p.h. (235 km/h) and there were wind gusts to 165 m.p.h. (265 km/h). The minimum surface pressure was 939 mb.

Tropical Cyclone Olga rapidly intensified to the equivalent of a Category 4 hurricane over the South Indian Ocean north of Western Australia during Sunday morning. A small circular eye with a diameter of 10 miles (16 km) was present at the center of Olga’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Olga. Storms near the core generated strong upper level divergence that pumped mass away from the tropical cyclone. The removal of large quantities of mass caused the surface pressure to decrease rapidly.

The circulation around Tropical Cyclone Olga was small. Winds to hurricane/typhoon force extended out 20 miles (30 km) from the center of Olga’s circulation. Winds to tropical storm force extended out 85 miles (135 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Olga was 28.3. The Hurricane Size Index (HSI) was 6.1 and the Hurricane Wind Intensity Size Index (HWISI) was 34.4.

Hurricane Olga will move into an environment that will become unfavorable for intensification during the next 24 hours. Olga will move over water where the Sea Surface Temperatures are near 28°C. An upper level trough over the South Indian Ocean will approach Tropical Cyclone Olga from the west. The trough will produce strong westerly winds that will blow toward the top of Olga’s circulation. Those winds will cause the vertical wind shear to increase. Tropical Cyclone Olga will start to weaken when the wind shear increases. Olga could weaken rapidly because of the small size of its circulation.

Tropical Cyclone Olga will move around the northwestern part of a high pressure system over Australia. The high pressure system will steer Olga toward the southwest during the next 24 hours. On its anticipated track, Tropical Cyclone Olga will move parallel to the coast of Western Australia. Olga is forecast to turn more toward the west-southwest on Monday. Tropical Cyclone Olga is expected to have a minimal impact on Western Australia. Olga will bring gusty winds and large waves to the area around Rowley Shoals.